|Publication number||US4790317 A|
|Application number||US 06/923,408|
|Publication date||13 Dec 1988|
|Filing date||27 Oct 1986|
|Priority date||25 Oct 1985|
|Also published as||DE3689816D1, DE3689816T2, EP0220916A2, EP0220916A3, EP0220916B1|
|Publication number||06923408, 923408, US 4790317 A, US 4790317A, US-A-4790317, US4790317 A, US4790317A|
|Inventors||David W. Davies|
|Original Assignee||Davies David W|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (5), Referenced by (56), Classifications (10), Legal Events (6)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This invention relates to apparatus for recognition of ventricular tachycardia and ventricular fibrillation from epicardial electrogram timings, and for termination thereof.
Ventricular fibrillation is defined as a condition characterized by fibrillary electrical activity of the ventricular muscle, the electrical impulses traversing the ventricles so rapidly that coordinated contractions cannot occur. This must be distinguished from ventricular tachycardia which may be defined as a rapid (greater than 100 beats per min.) cardiac rhythm originating in the ventricles. If sustained, it is usually synchronized in terms of overall ventricular contraction. Both should be differentiated from the normal situation of sinus rhythm where the heart's rhythm is controlled by depolarization originating from the sinus node and which spread sequentially through the atria, the AV node, the His-Purkinje system, and ventricular myocardium.
It is an object of the invention to provide an apparatus for recognizing both ventricular tachycardia and ventricular fibrillation, and means for responding to both these conditions to restore normal heart rhythm.
According to the present invention, an apparatus is provided for the automatic recognition of ventricular tachycardia and ventricular fibrillation. At least two sensors are provided, one sensor being attached at least to each ventricular epicardial surface of a heart. Signal paths connect the sensors to programmed means for detecting a pulse sequence representing the ventricular electrical activity of the heart and for comparing the pulse sequence detected with that representing the electrical activity of the heart during normal ventricular rhythm of the heart. Means are provided for converting the detected pulse sequence into a form which will be useful for providing a corrective response to a pulse sequence representing the electrical activity of the heart during abnormal ventricular rhythm of the heart. The apparatus is generally used in association with means for supplying to the heart stimuli to restore normal rhythm to the heart following detection of abnormal ventricular rhythm. In such a case there may be no need for converting the detected pulse sequence into a readable form or other form, such as audible form, which permits identification of a pulse sequence representing electrical activity of the heart during abnormal ventricular rhythm.
FIG. 1 shows schematically an arrangement of four ventricular activation sites;
FIG. 2 shows the electrograms obtained from the four sites during normal sinus rhythm;
FIGS. 3A, B, and C show electrograms obtained under simulated ventricular tachycardia conditions;
FIG. 4 shows the electrograms obtained at the four sites under conditions of ventricular fibrillation;
FIG. 5 is a block diagram of a cardiac implant embodying this invention; and
FIG. 6 is a flow chart indicating the characteristic operation of the present invention.
The feasibility of automatic recognition of ventricular tachycardia and ventricular fibrillation has been examined in a number of patients undergoing coronary artery surgery. Bipolar epicardial electrograms from four discrete points on the surface of the heart have been recorded during operation. The points are indicated on the ventricles of the heart. It has been observed that during normal rhythm, the points which are recorded are activated in a certain sequence which is at least consistent, although not always specific to that rhythm. Thus, referring to FIG. 1 of the accompanying drawings, the locations of four discrete points numbered A, B, C, and D on the left ventricle (LV) and right ventricle (RV) are shown, two of the points (A and D) being on the left ventricular and right ventricular apices, and points B and C being at left ventricular and right ventricular paraseptal positions. A pacing site is located on the right ventricle adjacent the third point. During normal rhythm, activation took place in the sequence C, D, B, A in this particular case (see FIG. 2). Furthermore, the timing from the first detected deflection to the last of the four was always the same during normal rhythm, and in this example, because of normal rhythm, the timing is short, and is of the order of 25 msec.
With abnormal rhythm, this timing will generally be increased and the sequence of activations changed.
This latter observation was established by simulation of an abnormal rhythm by pacing from the site on the right ventricle. It was observed that 8 out of a group of 10 patients paced at this particular site showed a change of sequence of activation compared with that seen during normal sinus rhythm. Recording of the sequences obtained showed that activations change from C, D, B, A to C, B, D, A. Another abnormality which was induced (because a normal conducting system was not used) was that the spread of activity took longer across the heart. Thus, the timing from the onset of depolarization detected first at site C and finally at site A took 85 msecs, as opposed to 25 msecs. FIGS. 3A, 3B, and 3C indicate that this duration and sequence of activation is not affected by the rate of the abnormal rhythm, provided that its site of origin remains constant.
While maintaining the same set of sites, further experimentation to induce ventricular fibrillation yielded further results of interest. Ventricular fibrillation was induced by putting AC current onto a heart under cardiopulmonary by-pass (this is a means of obtaining cardiac arrest and is often used during surgery). It was observed that during ventricular fibrillation, the electrical activity at all four sites was extremely rapid, and certainly more rapid than normally seen. However, there was no apparent fixed sequence of activation. The activity can therefore be described as asynchronous. Because of the asynchronous nature of activity, there can be no fixed duration of activity. Thus, this provides a means of using multi site testing to distinguish between ventricular tachycardia (where there is likely to be an altered sequence of depolarization compared with normal rhythm and an increased duration of activation over that occurring during normal sinus rhythm) and ventricular fibrillation when all this synchrony is lost and the electrical activity from different points in the heart becomes asynchronous.
The apparatus of the present invention is programmed to respond to ventricular tachycardia or ventricular fibrillation when they are observed based upon an altered sequence and duration of ventricular activation as detected by impulses sensed from the epicardial sensing sites.
The present invention is of particular value since ventricular fibrillation has so far been a very difficult rhythm to detect reliably in automatic fashion. Moreover, the energy required by an implantable device to treat ventricular fibrillation is likely to be higher than that required to treat ventricular tachycardia. Therefore, by the use of this technique, lower energies can be selected for termination of ventricular tachycardia, thus prolonging battery life. There is thus provided a reliable method for the first time of detecting ventricular fibrillation. The micro-computer utilized in the circuit for comparing the activation sequence with that during sinus rhythm can then control a defibrillator which can be discharged when a rhythm characteristic of ventricular fibrillation or ventricular tachycardia is detected. Appropriate software is provided for controlling the micro-computer.
FIGS. 5 and 6 show practical embodiments of the invention and should be viewed in conjunction with each other. Thus, an implant 1 (sensors are not shown in FIG. 5 but are preferably at positions such as shown in FIG. 1) will monitor heart beat rate at all times using a normal heart beat detector 2 having a time base and backup pacing control 4 whose operation is directed by a microprocessor 5 having a memory 6. Should a high heart rate be detected, then a detector 3 which is normally operating in backup mode is switched on and simultaneous multichannel sensing is carried out (FIG. 1 shows sensing at four sites being carried out). This number is adequate in general, and there is no reason why more or less than four sites may be used for testing, although the use of four sites has been found to be an optimum compromise between cost and sensitivity. The microcomputer 5 which is utilized with the detector and receives signals therefrom will check by means of memory 6 whether activation sequence and duration are compatible with sinus rhythm. If this is the case, then no action will be required. However, if the activation sequence and duration are not compatible with sinus rhythm, then provided that an activation sequence is synchronized indicating ventricular tachycardia, a response appropriate to treatment of ventricular tachycardia will be initiated, i.e. stimuli will be delivered by pulse generator 7. In certain cases which depend on the type of tachycardia, however, ventricular tachycardia may be located by a relatively low energy shock for an associated defibrillator 8. If the activation sequence is not synchronized, indicating that ventricular fibrillation is taking place, then operation of the defibrillator 8 will take place.
In the preferred embodiment of the invention and again referring to FIG. 5, the normal heartbeat detector employs a band pass filter which receives the heartbeat signal and connects it to a first input of a threshold comparator whose other input is connected to a reference. The detector 3 is a Tachy detector which is morphology sensitive. The time base and back-up pacer control 4 is the known control logic of the pace function and can be over-ridden by the microcomputer or microprocessor 5. The microprocessor is preferably formed of the Intel 8085 microprocessor chip and the memory 6 is a ROM memory, Intel 27C64. The defibrillator stage 8 generates stimulation pulses in known prior art fashion and such a typical stage is shown in U.S. Pat. No. 4,321,928.
Although various minor changes and modifications may be proposed by those skilled in the art, it will be understood that I wish to include within the claims of the patent warranted hereon all such changes and modifications as reasonably come within my contribution to the art.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US4088140 *||18 Jun 1976||9 May 1978||Medtronic, Inc.||Demand anti-arrhythmia pacemaker|
|US4384585 *||6 Mar 1981||24 May 1983||Medtronic, Inc.||Synchronous intracardiac cardioverter|
|US4427011 *||18 Mar 1982||24 Jan 1984||Telectronics Pty. Ltd.||Tachycardia control pacer with improved detection of tachycardia termination|
|US4473078 *||24 May 1982||25 Sep 1984||Cardiac Resuscitator Corporation||Cardiac arrhythmia analysis system|
|US4475551 *||2 Sep 1982||9 Oct 1984||Mieczyslaw Mirowski||Arrhythmia detection and defibrillation system and method|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US5002052 *||29 Aug 1988||26 Mar 1991||Intermedics, Inc.||System and method for detection and treatment of ventricular arrhythmias|
|US5010887 *||17 Nov 1989||30 Apr 1991||Siemens-Pacesetter, Inc.||Noise discrimination in implantable pacemakers|
|US5097832 *||9 Mar 1990||24 Mar 1992||Siemens-Pacesetter, Inc.||System and method for preventing false pacemaker pvc response|
|US5158079 *||25 Feb 1991||27 Oct 1992||Incontrol, Inc.||Implantable device for preventing tachyarrhythmias|
|US5193535 *||27 Aug 1991||16 Mar 1993||Medtronic, Inc.||Method and apparatus for discrimination of ventricular tachycardia from ventricular fibrillation and for treatment thereof|
|US5205283 *||30 Jul 1991||27 Apr 1993||Medtronic, Inc.||Method and apparatus for tachyarrhythmia detection and treatment|
|US5243976 *||25 Mar 1991||14 Sep 1993||Ferek Petric Bozidar||Tricuspid flow synchronized cardiac electrotherapy system with blood flow measurement transducer and controlled pacing signals based on blood flow measurement|
|US5243978 *||7 Oct 1991||14 Sep 1993||Medtronic, Inc.||Method and apparatus for wide area antitachycardia pacing|
|US5257621 *||29 Jan 1993||2 Nov 1993||Medtronic, Inc.||Apparatus for detection of and discrimination between tachycardia and fibrillation and for treatment of both|
|US5261418 *||23 Aug 1991||16 Nov 1993||Siemens Aktiengesellschaft||Cardiac lead with tensiometric element for providing signals corresponding to heart contractions|
|US5271392 *||27 Jan 1992||21 Dec 1993||Siemens-Elema Ab||Method and apparatus for administering cardiac electrotherapy dependent on mechanical and electrical cardiac activity|
|US5279291 *||3 Aug 1992||18 Jan 1994||Incontrol, Inc.||Method for atrial defibrillation|
|US5282837 *||12 Apr 1991||1 Feb 1994||Incontrol, Inc.||Atrial defibrillator and method|
|US5292348 *||13 Apr 1992||8 Mar 1994||Telectronics Pacing Systems, Inc.||Implantable cardioverter/defibrillator and method employing cross-phase spectrum analysis for arrhythmia detection|
|US5316001 *||22 Feb 1993||31 May 1994||Ferek Petric Bozidar||Cardiac measurement system for measuring blood flow velocity by use of a sensor implanted inside the heart|
|US5318595 *||8 May 1992||7 Jun 1994||Ferek Petric Bozidar||Pacing method and system for blood flow velocity measurement and regulation of heart stimulating signals based on blood flow velocity|
|US5366486 *||9 Feb 1993||22 Nov 1994||Indiana University Foundation||Automatic fibrillation detector and defibrillator apparatus and method|
|US5366487 *||4 Nov 1993||22 Nov 1994||Angeion Corporation||Fibrillation and tachycardia detection|
|US5403354 *||29 Aug 1994||4 Apr 1995||Incontrol, Inc.||Defibrillator and method utilizing three channel sensing|
|US5447519 *||19 Mar 1994||5 Sep 1995||Medtronic, Inc.||Method and apparatus for discrimination of monomorphic and polymorphic arrhythmias and for treatment thereof|
|US5476503 *||28 Mar 1994||19 Dec 1995||Pacesetter, Inc.||Sense array intelligent patch lead for an implantable defibrillator and method|
|US5496361 *||21 Jul 1994||5 Mar 1996||Pacesetter, Inc.||System and method for detecting cardiac arrhythmias using a cardiac wall acceleration sensor signal|
|US5549652 *||15 Nov 1993||27 Aug 1996||Pacesetter, Inc.||Cardiac wall motion-based automatic capture verification system and method|
|US5601609 *||14 Mar 1995||11 Feb 1997||Pacesetter, Inc.||Implantable cardiac stimulating device and method for administering synchronized cardioversion shock therapy to provide preemptive depolarization|
|US5620471 *||16 Jun 1995||15 Apr 1997||Pacesetter, Inc.||System and method for discriminating between atrial and ventricular arrhythmias and for applying cardiac therapy therefor|
|US5623936 *||5 Dec 1995||29 Apr 1997||Pacesetter, Inc.||Implantable medical device having means for discriminating between true R-waves and ventricular fibrillation|
|US5628777 *||14 Jul 1993||13 May 1997||Pacesetter, Inc.||Implantable leads incorporating cardiac wall acceleration sensors and method of fabrication|
|US5683447 *||19 Dec 1995||4 Nov 1997||Ventritex, Inc.||Lead with septal defibrillation and pacing electrodes|
|US5693074 *||5 Dec 1994||2 Dec 1997||Pacesetter Ab||Cardiac electrotherapy device for cardiac contraction measurement|
|US5868680 *||23 Sep 1997||9 Feb 1999||The Regents Of The University Of California||Quantitative characterization of fibrillatory spatiotemporal organization|
|US6539256 *||6 Jul 2000||25 Mar 2003||Cardiac Pacemakers, Inc.||Method and apparatus for treating cardiac arrhythmia using electrogram features|
|US6839591||24 Mar 2003||4 Jan 2005||Cardiac Pacemakers, Inc.||Method and apparatus for treating cardiac arrhythmia using electrogram features|
|US6855144||30 Aug 2002||15 Feb 2005||The Regents Of The University Of California||Tissue ablation device and method of use|
|US6872205||25 Apr 2002||29 Mar 2005||The Regents Of The University Of California||Circumferential ablation device assembly|
|US6932804||21 Jan 2003||23 Aug 2005||The Regents Of The University Of California||System and method for forming a non-ablative cardiac conduction block|
|US7044135||30 Aug 2002||16 May 2006||The Regents Of The University Of California||Device and method for forming a circumferential conduction block in a pulmonary vein|
|US7231249||24 Jul 2003||12 Jun 2007||Mirowski Family Ventures, L.L.C.||Methods, apparatus, and systems for multiple stimulation from a single stimulator|
|US7317950||24 Feb 2003||8 Jan 2008||The Regents Of The University Of California||Cardiac stimulation system with delivery of conductive agent|
|US7369890||9 May 2003||6 May 2008||Cardiac Pacemakers, Inc.||Technique for discriminating between coordinated and uncoordinated cardiac rhythms|
|US7425210||22 Dec 2003||16 Sep 2008||Cardiac Pacemakers, Inc.||Drug delivery system for implantable medical device|
|US7627373||25 Nov 2003||1 Dec 2009||Cardiac Pacemakers, Inc.||Method and apparatus for cell and electrical therapy of living tissue|
|US7664549 *||10 May 2005||16 Feb 2010||Cardiac Pacemakers, Inc.||Cardiac rhythm management system with arrhythmia classification and electrode selection|
|US7981065||20 Dec 2004||19 Jul 2011||Cardiac Pacemakers, Inc.||Lead electrode incorporating extracellular matrix|
|US7993337||12 May 2009||9 Aug 2011||The Regents Of The University Of California||Circumferential ablation device assembly|
|US8060219||20 Dec 2004||15 Nov 2011||Cardiac Pacemakers, Inc.||Epicardial patch including isolated extracellular matrix with pacing electrodes|
|US8249725||8 May 2007||21 Aug 2012||Mirowski Family Ventures, L.L.C.||Methods, apparatus, and systems for multiple stimulation from a single stimulator|
|US8639330||14 May 2010||28 Jan 2014||Cardiac Pacemakers, Inc.||Cardiac rhythm management system with arrhythmia classification and electrode selection|
|US8744558||27 Mar 2007||3 Jun 2014||Mirowski Family Ventures, L.L.C.||Method and apparatus for providing ipselateral therapy|
|US8761905||4 Jun 2012||24 Jun 2014||Mirowski Family Ventures, L.L.C.||Methods, apparatus, and systems for multiple stimulation from a single stimulator|
|US20050021096 *||24 Jul 2003||27 Jan 2005||Mirowski Family Ventures, L.L.C.||Methods, apparatus, and systems for multiple stimulation from a single stimulator|
|US20050055058 *||8 Sep 2003||10 Mar 2005||Mower Morton M.||Method and apparatus for intrachamber resynchronization|
|US20050203581 *||10 May 2005||15 Sep 2005||Cardiac Pacemakers, Inc.||Cardiac rhythm management system with arrhythmia classification and electrode selection|
|USRE39897||8 Aug 2002||23 Oct 2007||Mirowski Family Ventures, L.L.C.||Method and apparatus for treating hemodynamic disfunction|
|EP0340045A2 *||28 Apr 1989||2 Nov 1989||Telectronics N.V.||Apparatus and method for controlling multiple sensitivities in arrhythmia control system including post therapy pacing delay|
|EP0778050A2||4 Dec 1996||11 Jun 1997||Pacesetter Inc.||Implantable medical device having cardiac event detection system|
|WO1995019201A1 *||12 Jan 1995||20 Jul 1995||Ferec Petric Bozidar||Cardiac electrotherapy system with cardiac contraction sequence measurement|
|International Classification||A61B5/0402, A61N1/362, A61B5/0428, A61N1/38, A61N1/365|
|Cooperative Classification||A61N1/38, A61N1/3621|
|European Classification||A61N1/362A, A61N1/38|
|4 Jul 1989||CC||Certificate of correction|
|29 May 1992||FPAY||Fee payment|
Year of fee payment: 4
|23 Jul 1996||REMI||Maintenance fee reminder mailed|
|3 Sep 1996||FPAY||Fee payment|
Year of fee payment: 8
|3 Sep 1996||SULP||Surcharge for late payment|
|9 May 2000||FPAY||Fee payment|
Year of fee payment: 12